<div>
  When this option is checked, multiple builds of this project may be executed
  in parallel.
  <p>
    By default, only a single build of a project is executed at a time &mdash;
    any other requests to start building that project will remain in the build
    queue until the first build is complete.
    <br />
    This is a safe default, as projects can often require exclusive access to
    certain resources, such as a database, or a piece of hardware.
  </p>

  <p>
    But with this option enabled, if there are enough build executors available
    that can handle this project, then multiple builds of this project will take
    place in parallel. If there are not enough available executors at any point,
    any further build requests will be held in the build queue as normal.
  </p>

  <p>
    Enabling concurrent builds is useful for projects that execute lengthy test
    suites, as it allows each build to contain a smaller number of changes,
    while the total turnaround time decreases as subsequent builds do not need
    to wait for previous test runs to complete.
    <br />
    This feature is also useful for parameterized projects, whose individual
    build executions &mdash; depending on the parameters used &mdash; can be
    completely independent from one another.
  </p>

  <p>
    Each concurrently executed build occurs in its own build workspace, isolated
    from any other builds. By default, Jenkins appends "
    <code>@&lt;num&gt;</code>
    " to the workspace directory name, e.g. "
    <code>@2</code>
    ".
    <br />
    The separator "
    <code>@</code>
    " can be changed by setting the
    <code>hudson.slaves.WorkspaceList</code>
    Java system property when starting Jenkins. For example, "
    <code>hudson.slaves.WorkspaceList=-</code>
    " would change the separator to a hyphen.
    <br />
    For more information on setting system properties, see the
    <a
      href="https://www.jenkins.io/redirect/setting-system-properties"
      rel="noopener noreferrer"
      target="_blank"
    >
      website
    </a>
    .
  </p>

  <p>
    However, if you enable the
    <i>Use custom workspace</i>
    option, all builds will be executed in the same workspace. Therefore caution
    is required, as multiple builds may end up altering the same directory at
    the same time.
  </p>
</div>
